Tuberculosis and Johne s Disease Prof. R. S. Chauhan Joint Director, Indian Veterinary Research Institute Izatnagar 243 122 (India)
TUBERCULOSIS Tuberculosis is a chronic bacterial disease of animals caused by Mycobacterium sp. and characterized by presence of tubercle nodules in lungs, spleen and lymph nodes. 2
TUBERCULOSIS Etiology Mycobacterium tuberculosis M. bovis Have mycolic acid in cell wall Acid Fast 3
TUBERCULOSIS Pathogenesis Contact with infected animals, discharges, morbid tissues Organisms through sputum at coughing-droplet infection Fomites- instruments, utensils and beddings Localizes and produce typical tubercle in lymph node Mostly pharyngeal and mesenteric lymph nodes Inhaled organism enter in the bronchial tree Lungs- caseative necrosis Macrophages, epithelioid cells, giant cells, Lymphocytes Fibrous connective tissues formed around tubercle 4
Characteristic symptoms Low grade fever Progressive wasting/weakness, loss of production Coughing TUBERCULOSIS 5
TUBERCULOSIS Macroscopic features Consolidation of lungs Nodules of tubercle present in lungs containing cheesy mass Granulomatous lesions in spleen, lymph nodes, liver and intestines. Tubercle on pleura and mesentery -pearly disease 6
TUBERCULOSIS Microscopic features Granulomatous lesions tubercles Necrosed areamacrophages, lymphocytes, epithelioid cells and giant cells Necrosed area calcified and surrounded by fibrous tissue capsule 7
TUBERCULOSIS Diagnosis Symptoms and lesions Tuberculin testing of animals Immunodiagnostic tests Gamma- interferon assay T-lymphocyte blastogenesis assay Demonstration of acid fast bacilli 8
Treatment Not advisable TUBERCULOSIS Prevention and Control Isolation of sick animals Maintain hygienic conditions 9
Johne s Disease Johne s disease is a chronic bacterial disease of bovines, ovines and caprines caused by Mycobacterium paratuberculosis and characterized by dehydration, emaciation, chronic diarrhoea and thickening of the intestine (corrugations). 10
Etiology Johne s Disease Mycobacterium paratuberculosis Have mycolic acid in cell wall Acid fast 11
Johne s Disease Pathogenesis Faeces primary source of infection Ingestion of contaminated feed and water Localizes in intestinal mucosa, lymph nodes Residence within macrophages Multiplies, resistant to intracellular digestion Distributed in body from ileum, large intestine Decreased absorptive surface, chronic diarrhoea and malabsorption. 12
Characteristic symptoms Chronic diarrhoea Johne s Disease Progressive wasting/weakness, loss of production Hide bound conditions 13
Johne s Disease Macroscopic features Emaciation, cachexia Thickening of the intestinal wall Presence of rugae Corrugations cannot be removed even after stretching of intestinal wall Lymph nodes (Mesenteric) enlarged 14
Johne s Disease Microscopic features Infiltration of macrophages, epithelioid cells and lymphocytes Presence of acid fast bacilli in epithelioid cells Absence of caseative necrosis, calcification in cattle Present in sheep and goat Nests of epithelioid cells in mesenteric lymph nodes 15
Johne s Disease Diagnosis Symptoms and lesions Demonstration of acid fast bacteria in rectal pinch Johnin testing of animals Immunodiagnostic tests ELISA, AGID Demonstration of organisms in tissue 16
Johne s Disease Treatment Not advisable Prevention and Control Isolation of sick animals Maintain hygienic conditions 17
18